Description and History

NPL Listing History

NPL Status: Non-NPL

Proposed Date:

Final Date:

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The Northeast Church Rock Mine (NECR) is a former uranium mine located at the northern end of State Highway 566 approximately 17 miles northeast of Gallup, NM in the Pinedale Chapter of the Navajo Nation. NECR is immediately adjacent to the Navajo Reservation boundary and most of the 125-acre mine permit area is held in trust for the Navajo Nation by the United States Government. Approximately 40 acres are patented mining claim land owned by the United Nuclear Corporation (UNC). There is a small community of residents that live immediately next to the mine site on the Navajo reservation, downstream and downwind of the waste piles. The residents graze sheep, cattle and horses, and collect herbs around the area. Due to the proximity of the residents to the mine site, this mine was identified as the highest priority for cleanup by US EPA and Navajo Nation EPA of over 500 abandoned uranium mines on the Navajo Nation.

NECR was operated by UNC from 1967 to 1982. During this time, approximately 3.5 million tons of ore was extracted making this the second highest producing mine on the Navajo Nation behind the Kermac Mine No. 22 in the Ambrosia Lake Area. While the mine was in operation, the New Mexico Mining and Minerals Division regulated the site. The uranium ore body is located up to 1,800 feet below grade at the NECR Mine Site. Therefore, the mining was conducted over 1,000 feet below the ground surface accessed through two main underground shafts. Other mining features included several vent holes, support buildings, roads and water extraction wells and treatment facilities. Portions of the site are located within an arroyo. Uranium ore from the UNC mine was processed at the adjacent UNC Mill Site, located on private property across Highway 566.

When the mine was closed, several basic closure activities took place. The majority of the buildings and equipment were cleared from the area. Waste piles were contoured to reduce movement of the material. The ponds were drained and a fence was installed around the mine site and associated areas. Tailings from the UNC Mill were brought to the UNC Mine Site and used to fill and stabilize some portions of the mine that had been excavated to remove uranium ore. The tailings were pumped underground using sand slurry which filled the mine workings and shafts. The shafts were then capped with concrete plugs.

In 2005, the Navajo Nation requested that US EPA Region 9’s San Francisco Office take the lead in investigating and cleaning up the mine site. Through investigations beginning in 2006, US EPA has detected radium contamination above safe levels both on the mine site and in the surrounding areas on the Navajo Reservation immediately downwind and downstream of the mine site. Contamination discovered on the Navajo Reservation and in the residential areas was addressed through a series of short-term cleanup actions in 2007, 2009, and 2012. Contamination on the mine site is being addressed over a longer time period. On September 29, 2011, US EPA signed an Action Memorandum for the NECR site, selecting a cleanup plan for NECR that will bring low levels of contaminated waste from the NECR mine site to the UNC Mill Site for disposal. A Record of Decision for the UNC Mill Site was signed by US EPA in March of 2013. After a Pre-Design sampling effort in 2013-2014 to collect additional data on the Mill and Mine sites for input into the design, the project is currently under design. The NECR cleanup is contingent upon approval of a license amendment for the UNC Mill Site from the Nuclear Regulatory Commission.

Contaminants and Risks

Contaminated Media

Surface Water

Air

Soil and Sludges

Contaminants

Radionuclides: As uranium breaks down over time, it turns into radium. Radium is a radioactive substance that breaks down over time, releasing alpha, beta and gamma radiation. Radium may be found in air, water and soil and plants may absorb radium in the soil. Breathing in high levels of radium can cause adverse effects to the blood, eyes, lungs, and teeth. Exposure to high levels of radium can result in an increased incidence of bone, liver, and breast cancer. The U.S.EPA and the National Academy of Sciences, Committee on Biological Effects of Ionizing Radiation, have stated that radium is a known human carcinogen that can cause cancer (ATSDR, 1999).

Risks

Current conditions at the NECR Mine Site present risks due to the lack of an engineered containment system for the mine waste and the wind and water transport mechanisms that have previously contaminated the NECR Mine Site and the residential areas located north of the NECR Mine. The Human Health Risk Assessment indicated that there are three predominant human exposure pathways of concern for uranium and radium. Whole body radiation may be experienced by nearby residents and trespassers on or near the NECR Mine Site itself or at secondary sources (e.g., water or windborne). Radium in the soil may be absorbed by plants and may concentrate in terrestrial organisms. Persons and wildlife may also directly ingest radionuclides which then may be transported to organs or other sites in the body. Radionuclides such as radium, radon and decay products may be inhaled creating alpha radiation sources in the lungs.

Much of the contaminated material at the NECR Mine Site is fine-grained and therefore likely to result in human exposure via inhalation or ingestion. Persons occupying or traversing the NECR Mine Site may be exposed to contaminated dust by inhalation or ingestion of contamination sorbed to particulate matter. Incidences of direct contact with natural and mechanically generated dust during these activities account for known contamination exposure scenarios at the NECR Mine Site. Radium may be entrained in naturally and mechanically generated dust and/or transported on shoes and clothing of residents passing over contaminated areas.

Activities that could occur in contaminated areas that may put persons at risk include walking, hiking, livestock grazing, gardening and yard work, and modes of transportation including all-terrain vehicle, motorcycle, or horseback. Persons could drive their vehicles over contaminated areas as well. This activity may also contribute to exposure pathways via dust generation. Rainfall events may lead to transport of the contamination from the NECR Mine Site. Soil erosion may indicate transport of contamination from the NECR Mine Site constituting a release of hazardous substances and resulting in secondary contamination sources. In addition, contaminants may migrate during wind events, due to adherence to windborne dust particles.

Without the excavation and removal called for in the September 29, 2011 action memorandum (see Records of Decision section below), contaminated mine waste and soils from the NECR Mine Site may migrate off-site via wind and water transport mechanisms.
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Who is Involved

Northeast Church Rock Mine Site: US EPA Region 9 is the lead on the mine Site according to the terms of a Memorandum of Understanding (MOU) with the Navajo Nation and EPA Regions 6 and 8. US EPA is closely coordinating all site related activities with the Navajo Nation EPA.

UNC Mill Site: The UNC Mill Site is located across Highway 566 from the Northeast Church Rock Mine Site and EPA has selected the Mill Site for the repository for low levels of contaminated mine waste. EPA Region 6 has the lead for groundwater remediation, while the Nuclear Regulatory Commission (NRC) has the lead for soil remediation at the UNC Mill NPL Site, located on private property. Click here for more information about this mine site.

Investigation and Cleanup Activities

Initial Actions

In March 2005, the Navajo Nation Environmental Protection Agency (NNEPA) requested that the U.S. EPA (EPA) conduct a response action under the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) at the Site. In February 2006, the EPA submitted a consultation agreement to the NNEPA to conduct good faith government-to-government coordination of CERLCA response activities.

Site Studies

In November 2006, UNC, under order by the EPA, conducted a removal site investigation campaign to assess the 14 areas that are contaminated and to the severity of the contamination. EPA and NNEPA had several personnel overseeing the month-long effort. UNC collected 375 surface and subsurface soil samples and over 900 gamma survey points. A copy of the draft Removal Site Evaluation is located in the Technical Documents section.

Initial Actions

In April 2007, the EPA initiated a time critical removal action of radium contaminated soils from the three residences and side yards nearest the NECR mine site based upon validated data from the site investigation report. EPA addressed one additional yard close to the Kerr McGee site as a fund-lead (Residential Removal #2). The removal around the residences was viewed as a priority due to the high use immediately around the home sites. EPA chose an action level of 2.24 pCi/g Radium 226. Approximately .5 feet of soil from approximately 1/2 acre around each structure was excavated, stockpiled at the NECR mine. EPA conducted verification soil samples and 100% gamma scans prior to backfilling. Approximately 6,000 cubic yards of soil were trucked to an off-site radioactive TSD in Grandview, ID. A berm and french drain were installed as interim actions. Soils were backfilled and hydroseeded with native grasses. Residents were asked to participate in a temporary lodging program to minimize disruptions to their daily lives while removal activities occurred.

Site Studies

In Spring 2009 the EPA finalized an Engineering Evaluation and Cost Analysis (EE/CA) for the removal action at the remainder of the mine site (Non-Time Critical Removal Action). EPA held a ninety-day public comment period in the Summer, concluding on September 9, 2009.

Cleanup Ongoing

In 2009, EPA ordered UNC to conduct an Interim Time Critical Removal Action involving approximately 100,000 cubic yards of radium contaminated soil from the Step-Out Areas beyond the Mine Site, including the Unnamed Arroyo and vicinity residential areas. The work, with EPA oversight, involved excavation, consolidation and covering radium contaminated soils on the mine site. Excavation activities were substantially completed in January 2010 and UNC demobilized for the Winter. Fencing, reseeding, some additional excavation and installation of soil erosion control measures were accomplished in 2010.

Remedy Selected

On September 29, 2011, US EPA completed the action plan for the final cleanup of the Northeast Church Rock Mine site (See Figure 1, Area
A in the Northeast Church Rock Mine Cleanup Fact Sheet below). The location selected in the Action Memorandum, and determined to be suitable in the Engineering Evaluation and Cost Analysis previously issued, is the nearby United Nuclear Corporation (UNC) Mill Site. Placement of the waste at the Mill site is contingent upon amendment of the UNC Mill site facility’s NRC license. The plan is based on more than six years of work and over 10 public meetings with the local community, the Navajo Nation, and others to ensure that EPA heard, considered and responded to the questions and concerns of all stakeholders. The US EPA Region 6 Record of Decision for the UNC Mill Site Surface Soils was completed in March of 2013. UNC will submit the NRC License Amendment Request after the project design phase is completed.

Cleanup Ongoing

In 2012, EPA ordered UNC to conduct a Time Critical Removal Action involving approximately 30,000 cubic yards of radium contaminated soil in the Eastern Drainage Area from the Northeast Church Rock Mine Site. The work, with EPA oversight, involved excavation, consolidation, and covering radium contaminated soils on the mine site. Excavation Activities in the Eastern Drainage Area were complete in the Fall of 2012.

Remedy Design

In 2013 and 2014, UNC/GE, under federal agency oversight, completed extensive Pre-Design sampling and reporting on the mill tailings, barrow areas, and underlying formations at the UNC site as well as additional sampling of the NECR mine waste to provide additional information to support the design effort. In 2015, EPA signed an enforcement agreement with UNC/GE to complete the design for the long-term cleanup action. The design effort is currently underway.

Cleanup Results to Date

Initial site activities were conducted using Time Critical Removal Action authority cleaning up approximately 140,000 cubic yards of contaminated material on the reservation and temporarily storing the bulk of the material on the Mine Site until the final cleanup. Contaminated soil on the mine site will be addressed using Non-Time Critical Removal Action authority.

Potentially Responsible Parties

Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.

The United Nuclear Corporation (UNC), as the owner/operator of the facility, is a responsible party for the cleanup of the Northeast Church Rock Mine Site. UNC is a wholly-owned, indirect subsidiary of The General Electric Company (GE).